void main(){
  // List<String> foods =['西瓜',10,];
  List<String> foods =['西瓜','10',];

  Map<String,String> dog ={
    'name':'柯基',
    'color':'小黄',
    'age':'10'
  };
}

Future<num> getNum(){
  return Future((){
    return 10;
    // return '10';
  });
}

